2forloops

  for(int i=0; i<btn.length; i++){
        	for(int j=0; j<btn.length;j++){

        		//Initializing 2D buttons with values i,j
        		btn[i][j] = new Button(""+i+","+""+j);
        		btn[i][j].setPrefSize(50, 50); // Set pref size to buttons
        		gridPane.add(btn[i][j], i, j);  // Adding button to GridPane

        	}
        }